1,110 research outputs found

    Evolutionary responses of marine invertebrates to insular isolation in Galapagos

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    I examine the natural barriers to distribution and colonization that have shaped the Galapagos marine invertebrate biota. While diversity is high for some groups, such as hydroids and bryozoans, it is low for many others. Porcelain crabs and molluscs are examples with reduced or unbalanced representation in Galapagos, resulting from their dependency on dispersal of relatively short-lived planktonic larvae by ocean currents and on habitat limitations in Galapagos. Because Galapagos shorelines are predominantly rocky, without the wide expanses of silt typical of much of the Ecuadorian mainland that are favored by infaunal bivalves, gastropod diversity in Galapagos far exceeds that of bivalves. Nearly all hermatypic corals in Galapagos are members of the Panamic province; none is endemic to Galapagos. This suggests that colonization occurred by larval dispersal from there. The ahermatypic (azooxanthellate) coral fauna of Galapagos, with 43 species, is richer and more diverse than the hermatypic corals, with 29% of the shallow-water ahermatypes endemic and the remainder with Panamic, Indo-Pacific, and cosmopolitan affinities. The 73 verified species of Galapagos shallow-water echinoderms are dominated by Panamic species, with additional affinities to the Indo-Pacific and the California province; 8% are cosmopolitan and 8% endemic. With species richness roughly equivalent to that of Pacific Colombia, Galapagos echinoderm representation is not depauperate, but is sufficiently distinctive to characterize it as an isolated, insular biota. Hydroids and bryozoans, two groups with high diversity in Galapagos, accomplish long-distance transport mainly as adults on floating debris and hulls of ships, rather than by the free-swimming reproductive stage. Endemism among marine invertebrates averages 18.3 %, but varies widely among major taxa, from 0% for reef corals to 71% for gorgonians. Unlike the Galapagos terrestrial biota, in which endemic genera are common, the absence of endemic genera among marine invertebrates may be attributed to low isolation arising from greater dispersal and gene flow in the marine environment

    Peromyscus Populations as Related to Seasons and Vegetative Types at the Hardware Ranch, Cache County, Utah

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    Members of the genus Peromyscus, White-footed Mice, are known to occur in nearly all habitats of North America. Because of their numerical abundance and widespread distribution, these mice are extensively used in the study of the dynamics of animal populations. Thus, information perteining to the local distruibution and activities of these mice is of value to the more comprehensive studies that are being carried out in the field of zoological research

    Factors that influence traditional-age, high-achieving students to enroll at a research-extensive university in the Southern region of the United States

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    The primary purpose of this study was to determine if a model existed that significantly increased the researcher\u27s ability to accurately explain the enrollment status of high-achieving freshmen based on the influence of selected demographic and academic characteristics. Since World War II, the need for students to obtain an outstanding postsecondary education in order to compete for the best positions in today\u27s job market has become increasingly important. Thus, the need exists for higher education institutions to offer competitive academic programs that will attract top students and faculty. Since the number of graduating high school students is predicted to decline during the next decade, competition for students is fierce among institutions as enrollment managers strive to enroll outstanding students. This study\u27s population was defined as all high-achieving freshmen (ACT ≥ 28 and academic GPA ≥ 3.0) who were admitted to one selected research-extensive university for the fall 2005 semester. There were 13 independent variables that were collected from the admissions and student aid databases and then transferred to a computerized, recording form, which served as the research instrument. Using stepwise multiple discriminant analysis, the researcher identified a substantively and statistically significant model that increased the researcher\u27s ability to accurately explain the enrollment status of high-achieving freshman. The model correctly classified 65.0% of the cases, which was a 30.1% improvement over chance that was obtained on these subjects using this model. The variable that had the greatest impact on enrollment was whether or not the student\u27s parent graduated from the institution. Other variables that contributed significantly were: student\u27s residency status, college entrance examination score (ACT), gender, offer of admission to the Honors College, academic high school GPA, whether or not the student\u27s race was Hispanic, and whether the student graduated from a public or private high school. The researcher recommended additional studies that would increase the percentage of correctly classified students by integrating these variables with others that could further explain future freshman classes. Variables suggested were: the institution\u27s image, student\u27s academic major, high school counselor influence, student\u27s relationship with enrollment management offices, communication with students, and the campus visit program

    Preliminary survey of zooxanthellate zoanthids (Cnidaria : Hexacorallia) of the Galapagos, and associated symbiotic dinoflagellates (Symbiodinium spp.)

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    Despite their presence in almost all marine ecosystems, the zoanthids (Cnidaria: Hexacorallia: Zoantharia) are poorly studied, in large part due to a lack of useful morphological identification characters. Recent research combining morphology with DNA markers has begun to shed new light on diversity and distribution of the order Zoantharia. Here, preliminary findings on the diversity and distribution of zooxanthellate zoanthid species from the genera Zoanthus and Palythoa are presented, documenting these genera in the Galapagos for the first time. A brief description of the species found is provided. Zoanthus and Palythoa appear to be limited in the Galapagos to rocky shores in warm shallow sublittoral and infralittoral waters (minimum temperature >18°C), isolated from the colder water that dominates much of the archipelago. Preliminary results from the internal transcribed spacer region of ribosomal DNA sequences of symbiotic dinoflagellates suggest that both Zoanthus and Palythoa spp. in the Galapagos possess only Symbiodinium clade C. Brief descriptions of the zooxanthellate zoanthid species found in the Galapagos are provided

    Enabling Hybrid Architectures and Mesh Network Topologies to Support the Global Multi-Domain Community

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    The turn of the new decade also represents the dawn of a new shift in domain operations. Concepts such as “Space Dial Tone,” reliable global access to internet, on-demand Earth observation, and remote sensing, while still not fully realized, are no longer purely imaginative. These concepts are in high demand and are coupled with the goals of Global Multi-Domain Operations (MDO). Small satellites (smallsats) have emerged as functionally reliable platforms, driving the development of next-generation satellite constellations. To achieve the potential of tomorrow’s technology, these constellations must embrace space mission architectures based on interoperable, open-system constructs such as hybrid architectures and mesh network topologies. This paper presents the full timeline for realization of multi-node, disparate (sovereign, coalition, commercial, etc.) multi-domain (Space, Air, Maritime, Land, and Cyber) systems to support future space mission architectures. It identifies and discusses the underlying technologies needed to bring new “system-of-systems” concepts to operational capability. Technologies to be discussed include: message-agnostic physical/protocol “Bridges”; Machine-to-Machine (M2M) data sharing enabled through Electronic Data Sheet (EDS) standards; and, new concepts related to Artificial Intelligence (AI) enabled human decision making. Tying these technologies together effectively will positively impact the smallsat market and fundamentally change mission architectures in the near future
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